EP1437773A2 - Un courant d'obscurité réduit pour des capteurs d'images - Google Patents

Un courant d'obscurité réduit pour des capteurs d'images Download PDF

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Publication number
EP1437773A2
EP1437773A2 EP03078968A EP03078968A EP1437773A2 EP 1437773 A2 EP1437773 A2 EP 1437773A2 EP 03078968 A EP03078968 A EP 03078968A EP 03078968 A EP03078968 A EP 03078968A EP 1437773 A2 EP1437773 A2 EP 1437773A2
Authority
EP
European Patent Office
Prior art keywords
cmos image
image sensor
region
conductivity
substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP03078968A
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German (de)
English (en)
Other versions
EP1437773A3 (fr
Inventor
Eric G. Eastman Kodak Company Stevens
Robert M. Eastman Kodak Company Guidash
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
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Eastman Kodak Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of EP1437773A2 publication Critical patent/EP1437773A2/fr
Publication of EP1437773A3 publication Critical patent/EP1437773A3/fr
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F39/00—Integrated devices, or assemblies of multiple devices, comprising at least one element covered by group H10F30/00, e.g. radiation detectors comprising photodiode arrays
    • H10F39/80—Constructional details of image sensors
    • H10F39/803—Pixels having integrated switching, control, storage or amplification elements
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/10—Semiconductor bodies
    • H10F77/14—Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies
    • H10F77/147—Shapes of bodies

Definitions

  • the invention relates generally to the field of CMOS image sensors and, more particularly, to such image sensors having transfer gates having regions of enhanced conductivity in the substrate as defined by the area of the transfer gate.
  • CMOS image sensors 10 are solid state imagers built in a substrate 5 wherein each pixel typically contains a photo-sensing region 20, a reset transistor 30, a charge transfer region 40, a transfer gate electrode 45 separated from the substrate 5 by an insulating layer 42, a charge to voltage conversion region 50, and an amplifier 60.
  • dark current is generated in several regions of the device.
  • Such prior art devices have addressed dark current reduction in the photo-sensing region 20. Another region of dark current generation is the charge transfer region 40.
  • the charge transfer region 40 of current day CMOS image sensors is basically the channel region of a "normally on”, or depletion-mode type NMOSFET.
  • typical power supplies used in these CMOS systems are unipolar, (e.g., +3.3V).
  • the "off' state voltage on the transfer gate 45 of the CMOS sensor 10 is limited to a minimum of 0V (ground). Therefore, since the transfer gate's surface is not "turned off', a relatively high amount of dark current is generated in this region. This dark current, or a portion thereof, may leak into the photodiode during the integration period causing excess noise, thereby limiting the imaging performance of the device.
  • it is desirable to provide a charge transfer region 40 whose surface region will be accumulated (with holes) in the off state (Vg 0V) so as to quench this excess dark-current generation.
  • the present invention is directed to overcoming one or more of the problems set forth above.
  • the invention resides in a CMOS image sensor comprising (a) a substrate of a first conductivity type; (b) a photodetector for capturing incident light and converting it to a charge; (c) a transfer gate for passing the charge from the photodetector; and (d) a region of the first conductivity type of enhanced conductivity in the substrate which extends substantially along an entire length and width of the transfer gate.
  • the present invention has the following advantages of reducing dark current generated in the area of the transfer gate of a CMOS image sensor for reduced noise, increased dynamic range and overall improvement in image quality.
  • CMOS solid-state image sensor 65 are built in a substrate 73 wherein each pixel typically contains a photo-sensing region 69 for collecting incident light and converting this light to a charge during an integration period.
  • This photo-sensing region 69 may be a photodiode or a pinned photodiode, which is shown in Fig. 3 as a preferred embodiment.
  • a pinning layer 72 of the same conductivity type as the substrate is positioned atop a photodiode implant 70.
  • the photodiode implant 70 is of the opposite conductivity type to the substrate 73.
  • the sensor also includes a transfer region 75a of enhanced conductivity relative to that of the substrate 73 and a transfer gate electrode 76.
  • the transfer gate electrode 76 is separated from the substrate 73 by insulating materials 74.
  • An amplifier 100 is connected to the charge to voltage conversion region 80 for buffering the voltage to other circuitry on the chip, as is well known in the art.
  • the transfer region 75a is of enhanced conductivity relative to that of the substrate 73 for the purpose of reducing dark current generated in the area of the transfer gate. This reduced dark current provides reduced noise, increased dynamic range and overall improvement in image quality.
  • the substrate 73 is preferably of p-type conductivity and that the transfer region 75a is preferably of additional dopant of the same type as the substrate 73, p-type conductivity in this embodiment.
  • the enhanced p-type conductivity layer 75 extends substantially a length and width of the pinning layer 72 (typically formed by ion implantation) and becomes a portion of a pinning region 71.
  • the enhanced conductivity layer 75 includes a transfer region 75a and another portion 75b where the portion 75b is in the photo-sensing region 69. It is noted that the pinning region 71 is formed by the combination of the pinning layer 72 and enhanced p-type conductivity layer 75b.

Landscapes

  • Solid State Image Pick-Up Elements (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)
EP03078968A 2003-01-10 2003-12-18 Un courant d'obscurité réduit pour des capteurs d'images Ceased EP1437773A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US340487 2003-01-10
US10/340,487 US6730899B1 (en) 2003-01-10 2003-01-10 Reduced dark current for CMOS image sensors

Publications (2)

Publication Number Publication Date
EP1437773A2 true EP1437773A2 (fr) 2004-07-14
EP1437773A3 EP1437773A3 (fr) 2005-10-05

Family

ID=32176310

Family Applications (1)

Application Number Title Priority Date Filing Date
EP03078968A Ceased EP1437773A3 (fr) 2003-01-10 2003-12-18 Un courant d'obscurité réduit pour des capteurs d'images

Country Status (3)

Country Link
US (1) US6730899B1 (fr)
EP (1) EP1437773A3 (fr)
JP (1) JP2004221578A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100438057C (zh) * 2004-12-29 2008-11-26 东部亚南半导体株式会社 Cmos图像传感器及其制造方法

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JP3795843B2 (ja) * 2002-08-01 2006-07-12 富士通株式会社 半導体受光装置
US7250647B2 (en) * 2003-07-03 2007-07-31 Micron Technology, Inc. Asymmetrical transistor for imager device
US6900484B2 (en) * 2003-07-30 2005-05-31 Micron Technology, Inc. Angled pinned photodiode for high quantum efficiency
KR101026616B1 (ko) 2004-05-06 2011-04-04 크로스텍 캐피탈, 엘엘씨 시모스 이미지센서 및 그 제조방법
US7271430B2 (en) * 2004-06-04 2007-09-18 Samsung Electronics Co., Ltd. Image sensors for reducing dark current and methods of fabricating the same
JP2005347759A (ja) * 2004-06-04 2005-12-15 Samsung Electronics Co Ltd 暗電流を減少させるためのイメージセンサー及びその製造方法
US7214974B2 (en) * 2004-06-04 2007-05-08 Samsung Electronics Co., Ltd. Image sensors for reducing dark current and methods of manufacturing the same
KR100614650B1 (ko) * 2004-09-16 2006-08-22 삼성전자주식회사 이미지 센서 및 그 형성 방법
US7973836B2 (en) * 2004-10-28 2011-07-05 Omnivision Technologies, Inc. Camera, image sensor, and method for decreasing undesirable dark current
US7432543B2 (en) * 2004-12-03 2008-10-07 Omnivision Technologies, Inc. Image sensor pixel having photodiode with indium pinning layer
US7205627B2 (en) * 2005-02-23 2007-04-17 International Business Machines Corporation Image sensor cells
US7935994B2 (en) * 2005-02-24 2011-05-03 Taiwan Semiconductor Manufacturing Company, Ltd. Light shield for CMOS imager
KR100690884B1 (ko) * 2005-04-28 2007-03-09 삼성전자주식회사 이미지 센서 및 그 제조 방법
US7115924B1 (en) * 2005-06-03 2006-10-03 Avago Technologies Sensor Ip Pte. Ltd. Pixel with asymmetric transfer gate channel doping
KR100718781B1 (ko) * 2005-06-15 2007-05-16 매그나칩 반도체 유한회사 콤팩트 픽셀 레이아웃을 갖는 ｃｍｏｓ 이미지 센서
KR100699849B1 (ko) 2005-06-21 2007-03-27 삼성전자주식회사 국부적인 불순물 영역을 갖는 ｃｍｏｓ 이미지 소자 및 그제조방법
US20070023796A1 (en) * 2005-07-27 2007-02-01 International Business Machines Corporation Pinning layer for pixel sensor cell and method thereof
JP4657860B2 (ja) * 2005-09-16 2011-03-23 富士通株式会社 光送信装置および光通信システム
US8076225B2 (en) * 2005-11-07 2011-12-13 Sharp Kabushiki Kaisha Solid-state image capturing device, manufacturing method for the same and electronic information device
US7633134B2 (en) 2005-12-29 2009-12-15 Jaroslav Hynecek Stratified photodiode for high resolution CMOS image sensor implemented with STI technology
JP4758318B2 (ja) * 2006-09-29 2011-08-24 富士フイルム株式会社 固体撮像装置
US8760543B2 (en) 2011-09-26 2014-06-24 Truesense Imaging, Inc. Dark reference in CCD image sensors

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5625210A (en) * 1995-04-13 1997-04-29 Eastman Kodak Company Active pixel sensor integrated with a pinned photodiode
KR100278285B1 (ko) * 1998-02-28 2001-01-15 김영환 씨모스 이미지센서 및 그 제조방법
JP3934827B2 (ja) * 1999-06-30 2007-06-20 株式会社東芝 固体撮像装置
JP4449106B2 (ja) * 1999-07-14 2010-04-14 ソニー株式会社 Ｍｏｓ型固体撮像装置及びその製造方法
JP3688980B2 (ja) * 2000-06-28 2005-08-31 株式会社東芝 Ｍｏｓ型固体撮像装置及びその製造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100438057C (zh) * 2004-12-29 2008-11-26 东部亚南半导体株式会社 Cmos图像传感器及其制造方法

Also Published As

Publication number Publication date
EP1437773A3 (fr) 2005-10-05
JP2004221578A (ja) 2004-08-05
US6730899B1 (en) 2004-05-04

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